[GitHub] [arrow] emkornfield commented on a change in pull request #7346: ARROW-9029: [C++] Implement BitBlockCounter for much fast block popcounts of bitmaps

[GitBox <gi...@apache.org>]

emkornfield commented on a change in pull request #7346:
URL: https://github.com/apache/arrow/pull/7346#discussion_r434979894



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File path: cpp/src/arrow/util/bit_util.h
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@@ -1170,5 +1170,32 @@ class BitsetStack {
   std::vector<int> offsets_;
 };
 
+/// \brief A class that scans through a true/false bitmap to yield blocks of up
+/// to 256 bits at a time along with their popcount. This is used to accelerate
+/// processing of mostly-not-null array data.
+class ARROW_EXPORT BitBlockCounter {
+ public:
+  struct Block {
+    int16_t length;

Review comment:
       did you check if this affects benchmarks, I think popcount returns ints so there might be some miniscule advantage to keep it at a larger size.




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